1. Field of the Invention
The present invention relates to a package. More particularly, the present invention relates to a repairable multi-chip module.
2. Description of the Related Art
Typically, an integrated circuit (IC) manufacturing process includes three stages: wafer preparation, IC fabrication, and IC packaging. The purpose of the IC packaging is to provide an electrical medium between the die and the printed circuit board (PCB) or other proper devices and to protect the die.
In the integrated circuit module, a massive amount of the conductive wires is used to electrically connect the die and the substrate as the integration is increased. Typically, the die is electrically coupled to the PCB through a lead frame. When the integration of the integrated circuit becomes higher and the volume of the package is maintained or shrunk, the amount of the conductive wires between the die and the substrate is greatly increased. Therefore, the numbers of the conventional lead frame is insufficient. Several different package technologies such as chip scale package and chip size package (CSP) are developed to accommodate a massive amount of the conductive wires and to package the relatively complex circuit.
FIG. 1 is a schematic, cross-sectional view of a conventional multi-chip module (MCM) package. The MCM package comprises an MCM substrate 100, dies 108a and 108b, pads 102 and solder ball pads 104. The dies 108a and 108b and the pads 102 are located on one surface 116a of the MCM substrate 100. The solder-ball pads 104 are mounted on the other surface 116b of the MCM substrate 100. The pads 102 are electrically coupled to the solder-ball pads 104 through the electrical connecting paths 106. Each pad 102 on the MCM substrate 100 is electrically coupled to each pad (not shown) on the dies 108a and 108b through respective wires 110 formed by wire bonding. Additionally, the MCM package also comprises a resin used to cover the dies 108a and 108b, the wires 110, the pads 102 and the MCM substrate 100. Moreover, the MCM package further comprises several solder balls 114. The solder balls 114 mounted on the solder-ball pads 104 to form a ball grid array (BGA).
Typically, the electrically testing process is performed after the dies 108a and 108b are molded by the resin 112. Since the quality of the dies 108a and 108b in the multi-chip package (MCP) process are different, the yield and the reliability of the package product are worse. When the electrically testing result shows that the package product can not normally act and one of the dies 108a and 108b is failed, the reworking process can not be performed since the dies 108a and 108b are molded by the resin 112. Therefore, the other die with normal function is dumped with the MCM having the failed die formed therein. Hence, the cost is increased. If the repairing process is performed on the failed die, the wires 110 used to respectively electrically connect the pads 102 and the pads on the failed die should be removed. However, the substrate 100 is damaged by removing the wires 110. Hence, the yield and the reliability are decreased.